High performance RX antenna for a small lot - qsl.net · Jose Carlos N4IS 1919 March 5, 1919, Roy...

High performance RX antenna for a small lot

Jose Carlos N4IS

Receiver antennas for small lot

Basic concepts to receive weak signals

– Directivity & gain – RDF – Interaction and degradation – Urban noise – Receiver antenna definition

New olds receiver antennas

– Historic evolution – Single direction EWE FLAG DHDL – Rotatable antennas HWF VWF – High performance RX systems Dual DHDL; QDFA

RX antennas not sensible for man-made noise

– TX antenna interaction – Common mode noise – TX/RX leaking – Polarization filter HWF – Twisted pair lines – HWF single loaded loop construction – HWF dual loaded loop construction – Multiples loaded loops RX arrays –

Basic concepts

Jose Carlos N4IS

RX antennas directivity & gain

• It all about signal noise ratio • Minimum Detected signal “MDS”

Signal 30db above noise

Bandwidth

Noise floor

Signal at noise level

The ability to copy a weak signal depends mainly on the difference between the signal and receiver output noise

• The gain is the difference between an amplifier input and output intensity. – Adding a 18 db gain amplifier, the signal and the noise will increase

18db and the signal noise still will be the same.

-38 dbm

-20 dbm

28 db SN

28 db SN

RX antennas directivity & gain

40 db SN

30 db SN

1840 KHz carrier received with vertical TX antenna

Same signal received with a Big Waller Flag

RX antennas directivity & gain

RX antennas directivity & gain

When the signal is above noise there is little difference on the audio. The receiver AGC will make the strong signal just more comfortable to copy but it should not be used for evaluation of the receiver antenna.

A good receiver antenna will provide copy of weak signals not present or buried in the

noise on the transmit antenna

Directivity & RDF

Sinal de DX

QRN

QRM

QRN

QRN

QRM

Sinal de DX

QRN

QRM

QRN

QRN

QRM

Directivity & RDF

RDF

•RDF= Gain – Average Gain

RDF for known antennas 5 dB

6 dB

7 dB

8 dB

9 dB

10 dB

11 dB

12 dB

VERTICAL 1/4

Inverted V 160m 40m de altura

Dipole 160m 20 m high

EWE 160m / 80m

Horizontal Flag single element

Flag vertical

DHDL

DHDL X Beverage 1 wave

Beverage 2 waves long

Waller Flag

180

40 25

10

Dipole Inverted V

HWF Beverage 1 wave

Waller Flag

Vertical

RDF

8 dB

9 dB

10 dB

11 dB

12 dB

13 dB

14 dB

15 dB

RDF

4 square

Yagi - 2 elements

Quad - 2 elements Yagi - 3 elements

Yagi - 5 elements

2 Element vertical Horizontal HF

(PY2XB PY1RO)

HWF 3.5 MHz WF N4IS 160 80 40 m

3 x WF

4 x WF or EWE 4 x DHDL

RDF for known antennas

Power line noise at home

N4IS

2 Km

5 Km 2,7 Km

s 2

s 9

s 7

( -73 dBm )

( -88 dBm )

( -77 dBm )

Noise during the day with no QRN - 90 dBm

What we can really hear?

SSB 3 db 2,5KHz CW 0 db 100Hz

160 80 40 20

S 9

S 0

160 m 47 dBm 42 30 80 m 35 dBm 30 22 40 m 20 dBm 15 10

RECEIVER NOISE FLOOR

New RX antennas

Jose Carlos N4IS

1919 March 5, 1919, Roy A. Weagant, Chief Engineer of the Marconi Wireless Telegraph Co. of America, delivered a paper describing in detail his apparatus for the elimination of the great bug-bear of transoceanic wireless communication -- static interference. >> http://infoage.org/html/wa-1919-04-p11.html

1995 JF1DMQ wrote an earlier article about the Flag antenna in November 1995 in a Japanese magazine. His was only 3.3 feet by 16.4 feet long (1 by 5 m).K6SE's 160m optimized versions are 14 by 29 feet (4.3 by 8.8m).

1995 "Is This EWE for You?" (QST February, 1995, p.31) and "More EWES for You",

QST January, 1996, p. 32) both by WA2WVL.

1996 The Pennant was originated by EA3VY and optimized for 160 meters by K6SE, who first wrote about them on the Top Band Reflector in 1998

1997 The K9AY Terminated Loop—A Compact, Directional Receiving Antenna By Gary Breed, K9AY

1998 W7IUV rotatable Flag and preamplifier >> http://w7iuv.com/ 2000 QST Magazine, July 2000, page 34 for K6SE's classic article: "Flags, Pennants, and Other Ground-

Independent Low-Band Receiving Antennas" ...

2003 NX4D developed the first dual flag vertical array 2006 N4IS developed the BIG flag vertical array >> www.n4is.com

2008 N4IS developed the Horizontal flag array

2009 Dr Dallas Lankford, wrote the Flag Theory and design the Quad Flag Array >> http://www.kongsfjord.no/dl/dl.htm 2009 AA7JV George Wallner developed the DHDL (TX3A) >>

http://tx3a.com/docs/TX3A_DOUBLE_HALF_DELTA_LOOP.ZIP 2009 DOUBLING the Double Half-Delta Loop Receiving Antenna

by Pierluigi “Luis” Mansutti IV3PRK >> http://www.iv3prk.it/user/image/..-rxant.prk_tx3a.pdf

History of Flag RX antenna

Flag evolution 1919

http://infoage.org/html/wa-1919-04-p11.html

To a large and enthusiastic audience composed of radio engineers and scientists of prominence, at a joint meeting of the Institute of Radio Engineers and the New York Electrical Society, held March 5, 1919, Roy A. Weagant, Chief Engineer of the Marconi Wireless Telegraph Co. of America, delivered a paper describing in detail his apparatus for the elimination of the great bug-bear of transoceanic wireless communication -- static interference.

Antenas giratótias HWF VWF

Flag EWE Delta Pennant etc.

+ Resistor and Transformer

Two vertical in phase RDF = 8.25 dB

EWE RDF = 7.02 dB

Flag Array Dual Waller Flag

Resistor

Transformer signal

Two loops end fire

Dual Half Dual Loop AA7JV

Dual DHDL Quad WF

QUAD DHDL and Quad WF

Twisted pair

Waller Flag feed system

Transformer 9:1

NX4D BIG Vertical Waller Flag

15 m

8 m

N4IS Vertical Waller Flag VWF

15 m

N4IS Horizontal Waller Flag HWF

N4IS Horizontal Waller Flag HWF

PY1RO single HWF

PY1RO single HWF

PY2XB Single HWF

HWF

50 MHz yagi

50 MHz yagi

N8PR WF with polarization rotation.

N2NL WF all PVC

W8VVG WF

TX3A ( AA7JV ) DHDL

G0JHC DHDL

N4IS all metal WF 2009

New solution to fight power line

noise

Jose Carlos N4IS

Polarization filter HWF

- 30 db

HWF

Polarization filter HWF

N4IS Horizontal Waller Flag 2012

N4IS Horizontal Waller Flag 2012

N4IS preamps

RF CHOKE

http://audiosystemsgroup.com/publish.htm

http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf

http://audiosystemsgroup.com/RFIHamNCCC.pdf

Coaxial Transmitting Chokes Jim Brown K9YC

AC filter at N4IS

AC filter at N4IS

Don’t need to move out in the woods, just improve your receiving system and enjoy the good stuff.